Setting device for a vehicle having a mechanically adjustable part, and method for operating the setting device

ABSTRACT

A sensor ( 3, 4 ) is assigned to a mechanically adjustable part (e.g.  1 ) and generates sensor signals corresponding to the positions of the part. An initial range (sr) of the sensor values (s) is assigned to an inoperative position of the part and covers the varying initial positions of the part (e.g.  1 ). An evaluation device ( 9 ) stores a longer constant signal in the initial range as an intermediate value (st). A longer constant sensor signal is compared with the intermediate value (st) after the initial range (sr) is exceeded and after the subsequent return into this range. If it is established that both values are approximately of the same magnitude, the evaluation device stores this value as an initial value (sp, spn). As a result, the inoperative position of the part is reliably verified without the use of additional auxiliary means.

[0001] The invention relates to a setting device for a motor vehicle with a mechanically adjustable component and a process for operating the setting device.

[0002] It is typical in automobiles to couple a setting element, designed, for example, as a foot lever, with a sensor, which detects the angular position of the lever. The position signal of the lever is adjusted after installation into the automobile, in that in a stop position of the foot lever an auxiliary signal is set by way of an external signal input, or in that the position of the sensor itself is adjusted mechanically. The signal level, pending at the sensor in this instant, is then stored as the output signal and subtracted or compared in a subsequent operation. The reliability of the process can hardly be guaranteed according to automobile aspects. It is possible during subsequent operation of the motor vehicle that the geometry of the lever unit changes, for example, due to increasing bearing play, by means of deformations or in the event of a repair. Even the sensor, designed, for example, as a rotary potentiometer or Hall sensor, can change its characteristics through wear and contamination, for example, with ice particles. The properties of the electronic components will also vary in operation due to aging and environmental influences, a factor that can result automatically in a signal drift.

[0003] Conventional adaptive learning systems cannot be applied here, since the actuating profiles of the signals are a function of both the driver and the traffic situation, such as an uncontrolled long dwell period in a specific position. Furthermore, known algorithms cannot measure the short-term zero point changes, such as those that occur, for example, after a repair.

[0004] The DE 3612904 A discloses a process for the tolerance compensation of a position sensor signal, wherein the neutral position of the component is monitored during the operation of the motor vehicle. In this respect the measured values of an upper or a bottom stop are stored. Should one of these end values be exceeded during operation, the new measured value is stored as the new end value. This feature has the drawback that an actual drift of the neutral position toward the medium range cannot be detected at all.

[0005] The invention is based on the problem of eliminating the adjustment cost and increasing the functional reliability.

[0006] This problem is solved by means of the invention in accordance with claim 1. Owing to the constant monitoring of the neutral position during operation, shifts of the signal level in the stop position can now be detected and corrected. A subsequent adjustment by expert personnel is no longer necessary. A special advantage lies in the fact that fewer high requirements have to be imposed on the stability, quality and assembly of the setting device in order to guarantee its function.

[0007] A shift in the neutral value can be recognized reliably in both directions. Owing to the principle of repeating an initial value in a prolonged dwell position, it is possible to verify the neutral position with high certainty. It is also conceivable to fix the starting position at the instant that the vehicle electronics is switched on. If, however, at this instant, for example, the clutch pedal was actuated, the result is a misinterpretation with a corresponding malfunction of the operating system. In addition, the signal displacements would not be detectable in operation due to temperature variations. Since it is almost impossible to hit and hold a free floating position precisely multiple times in succession, it can be assumed with high certainty that at least a single repetition of a holding position within an initial range of the sensor signals represents the actual starting position. Thus, by means of this scheme the starting position is, in fact, detected dynamically, but not affected by vibrations, which occur, for example, in automobiles.

[0008] Advantageous further developments of the invention follow from the features, characterized in claims 2 to 4.

[0009] By means of the further development, according to claim 2, the setting device can be prepared and installed as a largely autonomous system without the need for any further tuning measures.

[0010] The resetting device, according to claim 3, guarantees in a simple manner the neutral position.

[0011] The further development, according to claim 4, provides an operating device, which can be produced easily with high functional reliability and can be installed into an automobile. A coil of the inductive sensor can be fastened, for example, to a pedal housing; and a metal part, grasped by the coil, can be fastened to a foot lever. Related control electronics is also fastened to the pedal housing and combined with the coil to form a module, which can also contain the evaluating electronics. The inductive sensor detects the distance to the metal part and thus also the angular position of the foot lever.

[0012] The inventions, according to claims 5 and 6, disclose the exact procedure for determining the initial value. In so doing, the degree of verification can be increased even more, when, after another repetition of the exact neutral level, the output signal is recognized and stored. Such a multiple repetition follows, for example, upon actuation of the clutch pedal in a starting phase.

[0013] One embodiment of the invention is depicted in the drawing and is explained below in detail.

[0014]FIG. 1 is schematic drawing of a partial side view of a pedal arrangement of an automobile with a distance sensor in a starting position.

[0015]FIG. 2 depicts the parts, according to FIG. 1, in another functional position.

[0016]FIG. 3 is a curve diagram of the sensor values as the position of the pedal arrangement, according to FIG. 1, changes.

[0017] According to FIG. 1, a mechanically adjustable component in the form of a foot lever 1, serving as an operating element, is disposed in a housing 5 so as to pivot about a pedal axis 2. Said housing can be installed into the foot space of an automobile. Above the foot lever 1 there is a stationarily mounted coil element 3, which induces an electromagnetic alternating field aimed in the direction of the foot lever 1. The coil element 3 is a part of a module 6, which is fastened to the housing and which is fastened to the housing 5 and which contains a control and evaluating electronic unit for the coil element.

[0018] Fastened to the foot lever 1, which is made, for example, of glass fiber reinforced plastic, there is a metal part 4, which together with the coil element forms an inductive sensor and whose distance to the coil element 3 changes as a function of the tilt position of the foot lever 1. This brings about a corresponding change in the inductive resistance of the coil element 3, a factor that results in a corresponding change in the measurable lost power of the coil element 3. The metal part 4, which is made of bent sheet metal, exhibits a convex cam-like curvature, whose contour is shaped in such a manner that the output signals of the sensor vary approximately in proportion to the angular position of the foot lever 1.

[0019] The metal part exhibits a flectional contour, which is easy to produce, and can be connected to the foot pedal with little effort by inserting into a casting mold for the foot lever. Therefore, this part of the sensor incurs almost no additional cost when subsequently installed into the pedal space. In the illustrated starting position, the foot lever rests against a stop 8 of the housing 5 against the force of a reset spring 7 and, in so doing, assumes a neutral position, whose sensor value represents a corresponding initial value. One end of the metal part is closely adjacent to the coil element and has a correspondingly strong impact on its electromagnetic alternating field.

[0020] According to FIG. 2, the foot lever swings into a functional position, in which the distance to the coil element 3 is significantly enlarged. The inductive resistance of the coil element has changed correspondingly. In a directly coupled converter (not illustrated) the sensor values can be converted into output signals and can be processed in an electronic evaluating unit of the module 6.

[0021]FIG. 3 reproduces the curve of the sensor values during one operating cycle, where t denotes the one time axis and s the axis of the sensor values. A threshold value sw, which is stored in the evaluating unit 9 (FIG. 1), defines an initial range sr of the sensor values, within which the initial value can vary. A past initial value sp is stored in the evaluating unit. On the left hand side of the curve the foot lever is in the stop position, according to FIG. 1. The sensor value s lies here significantly above the stored past initial value sp. Since the setting device, provided with a time element, does not exhibit any additional sensor, for example, in the form of an end probe for detecting the stop position, it assumes in the sensor value, which is constant over a defined minimum duration tm, below the threshold value sw a new initial value, which it stores as the temporary intermediate value st.

[0022] In the subsequent phase the foot lever 1 is swung out of its starting position into the functional position, shown in FIG. 2, where the sensor values s clearly exceed the threshold value sw. After the foot lever has returned into the starting position, shown in FIG. 1, the sensor values s reach in the right hand side of the curve exactly the amount of the intermediate value st, which remains constant over the specified minimum duration tm. The evaluating unit 9 compares this value with the intermediate value st. Upon adequate agreement between the two values and significant deviation from the stored initial value sp, the evaluating unit stores the intermediate value st as the new initial value spn for the neutral position of the foot lever 1 (FIG. 1).

[0023] Such a setting device and such an adjustment procedure can be applied not only to operating elements of a motor vehicle, but also to other setting and drive devices with cyclic sequences, for example in a carburetor or an injection system. The verification of the neutral position through exact repetition renders additional evaluations, for example, of probe positions or the current pickup of control drives superfluous. A special advantage lies in the fact that the device can work with the related sensor totally independent of other variables, a factor that makes it possible to largely separate the different measurement and control devices of the motor vehicle.

REFERENCE NUMERALS AND CHARACTERS

[0024]1 foot lever

[0025]2 pedal axis

[0026]3 coil element

[0027]4 metal part

[0028]5 housing

[0029]6 module

[0030]7 reset spring

[0031]8 stop

[0032]9 evaluating unit

[0033] s sensor value

[0034] sw threshold value

[0035] st intermediate value

[0036] sp initial value

[0037] spn n new initial value

[0038] sr initial range

[0039] t time

[0040] tm minimum duration 

1. Setting device for a motor vehicle with a mechanically adjustable component (for example, 1) and with a sensor (3, 4), which measures the positions of the component and which is connected to an electronic evaluating unit (9), where a neutral position of the component can be defined as the starting position, where the values (s) of the sensor signals that correspond to the neutral position can be stored in the evaluating unit (9) as the initial value sp, where the neutral position of the component can be monitored as the motor vehicle is operating, and where as the sensor signals deviate significantly in the neutral position from the initial value (sp), the value of the current sensor signals can be stored as the new initial value (spn), characterized in that the evaluating unit is provided with means for recognizing a setting cycle, that a prolonged stationary dwell position of the component (for example, 1) in an initial range (sr) of the neutral position can be stored in the evaluating unit (9), and that the departure from the initial range (sr) and the approximately exact return into the stored stationary dwell position and the prolonged dwelling therein can be stored as the actual neutral position.
 2. Setting device, as claimed in claim 1, characterized in that the component (1) is designed as an operating element and that the sensor (3, 4) and at least parts of the evaluating unit (9) are combined into a common module (6) and are connected to a housing (5) for the operating element.
 3. Setting device, as claimed in claim 2, characterized in that the operating element (for example, 1) is provided with a reset device (for example, 7), which upon release of the operating element moves it into the starting position.
 4. Setting device, as claimed in claim 3, characterized in that the operating element is designed as a spring-loaded swing lever, in particular as a foot lever (1); and that the sensor (3, 4), designed as an inductive distance sensor, detects the angular positions of the swing lever (for example, 1).
 5. Process for operating a setting device, as claimed in any one of the preceding claims, where the position of a mechanical component (for example, 1) is detected by means of a sensor (3, 4), which is coupled to an electronic evaluating unit (9), characterized in that to determine the starting position of the component, the sensor signals are assigned a threshold value (sw), which is stored in the evaluating unit (9), that the sensor signals, lying below the threshold value, are assigned to the initial range (sr), which corresponds to the allowable range of the neutral position, that the operating cycle is defined by exceeding the threshold value (sw) and subsequent return of the sensor values (s) into the initial range (sr), that the evaluating unit detects the signal level of the sensor continuously or in narrow time intervals and compares with the threshold value (sw), that the value of a sensor signal, which is constant over a minimum duration, below the threshold value in the evaluating unit is recognized and stored as the intermediate value (st), that upon exceeding and then dropping below the threshold value (sw), the signal level is compared with the intermediate value (st) and the initial value (sp), and that a sensor signal (s) that is then constant over the minimum duration, in the amount of the intermediate value, which deviates from the initial value (sp), is stored as the new initial value (spn).
 6. Process, as claimed in claim 5, characterized in that the starting position of the operating element is also monitored during the operation of the automobile and is redefined upon adequate deviation. 